From: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
To: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
LKML <linux-kernel@vger.kernel.org>, KVM <kvm@vger.kernel.org>
Subject: [PATCH 0/7] KVM: optimize memslots searching and cache GPN to GFN
Date: Tue, 22 Feb 2011 16:08:24 +0800 [thread overview]
Message-ID: <4D636EF8.60800@cn.fujitsu.com> (raw)
I noticed paging64/32_walk_addr_generic and gfn_to_memslot are very hot in kvm
modules:
# perf report
# Events: 38K cycles
#
# Overhead Command Shared Object Symbol
# ........ ............... .................. ......
#
6.73% qemu-system-x86 [kernel.kallsyms] [k] native_read_tsc
4.51% qemu-system-x86 [kernel.kallsyms] [k] delay_tsc
3.93% qemu-system-x86 [kvm] [k] paging64_walk_addr_generic
3.91% qemu-system-x86 [kernel.kallsyms] [k] arch_local_irq_restore
3.28% qemu-system-x86 [kvm_intel] [k] vmx_vcpu_run
3.12% qemu-system-x86 [kernel.kallsyms] [k] lock_acquire
3.10% qemu-system-x86 [kernel.kallsyms] [k] paravirt_read_tsc
2.70% qemu-system-x86 [kernel.kallsyms] [k] copy_user_generic_string
2.30% qemu-system-x86 [kernel.kallsyms] [k] check_flags
2.15% qemu-system-x86 [kernel.kallsyms] [k] do_raw_spin_lock
2.03% qemu-system-x86 [kvm] [k] gfn_to_memslot
The aim of this patchset is to reduce the overload of these two functions, it
does:
- sort memslots by ->base_gfn and use binary search to search the right slot
which is implemented by patch 1 ~ patch 7
- cache guest page number to frame number to reduce *_walk_addr_generic called,
and patch 7 does it.
After the patchset:
# Events: 36K cycles
#
# Overhead Command Shared Object Symbol
# ........ ............... .................. ......
#
5.64% qemu-system-x86 [kernel.kallsyms] [k] native_read_tsc
4.27% qemu-system-x86 [kvm_intel] [k] vmx_vcpu_run
3.85% qemu-system-x86 [kernel.kallsyms] [k] delay_tsc
3.32% qemu-system-x86 [kernel.kallsyms] [k] arch_local_irq_restore
2.68% qemu-system-x86 [kernel.kallsyms] [k] paravirt_read_tsc
2.41% qemu-system-x86 [kernel.kallsyms] [k] lock_acquire
2.25% qemu-system-x86 [kernel.kallsyms] [k] copy_user_generic_string
2.14% qemu-system-x86 [kvm] [k] kvm_mmu_pte_write
1.82% qemu-system-x86 [kernel.kallsyms] [k] check_flags
1.80% qemu-system-x86 [kvm] [k] paging64_walk_addr_generic
[......]
[......]
0.81% qemu-system-x86 [kvm] [k] gfn_to_memslot
There is the Unixbecn(the parameter is -c 10 fsdisk) test report:
Before patchset:
2090.5
1882.5
1845.2
After vtlb patch:
2237.4
2151.8
2118.0
After memslots sorted patches:
2392.5
2485.9
2416.1
next reply other threads:[~2011-02-22 8:08 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-22 8:08 Xiao Guangrong [this message]
2011-02-22 8:09 ` [PATCH 1/7] KVM: cleanup memslot_id function Xiao Guangrong
2011-02-22 8:10 ` [PATCH 2/7] KVM: introduce KVM_MEM_SLOTS_NUM macro Xiao Guangrong
2011-02-22 8:11 ` [PATCH 1/3] KVM: introduce memslots_updated function Xiao Guangrong
2011-02-22 8:12 ` [PATCH 4/7] KVM: sort memslots and use binary search to search the right slot Xiao Guangrong
2011-02-22 14:25 ` Avi Kivity
2011-02-22 14:54 ` Alex Williamson
2011-02-22 18:54 ` [RFC PATCH 0/3] Weight-balanced binary tree + KVM growable memory slots using wbtree Alex Williamson
2011-02-22 18:55 ` [RFC PATCH 1/3] Weight-balanced tree Alex Williamson
2011-02-23 13:09 ` Avi Kivity
2011-02-23 17:02 ` Alex Williamson
2011-02-23 17:08 ` Avi Kivity
2011-02-23 20:19 ` Alex Williamson
2011-02-24 23:04 ` Andrew Morton
2011-02-22 18:55 ` [RFC PATCH 2/3] kvm: Allow memory slot array to grow on demand Alex Williamson
2011-02-24 10:39 ` Avi Kivity
2011-02-24 18:08 ` Alex Williamson
2011-02-27 9:44 ` Avi Kivity
2011-02-22 18:55 ` [RFC PATCH 3/3] kvm: Use weight-balanced tree for memory slot management Alex Williamson
2011-02-22 18:59 ` [RFC PATCH 0/3] Weight-balanced binary tree + KVM growable memory slots using wbtree Alex Williamson
2011-02-23 1:56 ` Alex Williamson
2011-02-23 13:12 ` Avi Kivity
2011-02-23 18:06 ` Alex Williamson
2011-02-23 19:28 ` Alex Williamson
2011-02-24 10:06 ` Avi Kivity
2011-02-24 17:35 ` Alex Williamson
2011-02-27 9:54 ` Avi Kivity
2011-02-28 23:04 ` Alex Williamson
2011-03-01 15:03 ` Avi Kivity
2011-03-01 18:20 ` Alex Williamson
2011-03-02 13:31 ` Avi Kivity
2011-03-01 19:47 ` Marcelo Tosatti
2011-03-02 13:34 ` Avi Kivity
2011-02-24 10:04 ` Avi Kivity
2011-02-23 1:30 ` [PATCH 4/7] KVM: sort memslots and use binary search to search the right slot Xiao Guangrong
2011-02-22 8:13 ` [PATCH 5/7] KVM: cache the last used slot Xiao Guangrong
2011-02-22 14:26 ` Avi Kivity
2011-02-22 8:15 ` [PATCH 6/7] KVM: cleanup traversal used slots Xiao Guangrong
2011-02-22 8:16 ` [PATCH 7/7] KVM: MMU: cache guest page number to guest frame number Xiao Guangrong
2011-02-22 14:32 ` Avi Kivity
2011-02-23 1:38 ` Xiao Guangrong
2011-02-23 9:28 ` Avi Kivity
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